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Earnings Per Share (Narrative) (Details) - January 2016 Share Repurchase Program | 6 Months Ended |
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Jun. 30, 2016 $ / shares shares | Jan. 25, 2016 USD ($) capital_program
Earnings Per Share Disclosure [Line Items] |  |
Capital expenditure and stock repurchase program, approved amount (up to) | $ |  | $ 500,000,000
Capital expenditure and stock repurchase program, number of capital programs | capital_program |  | 2
Stock repurchase program, shares acquired (in shares) | shares | 2,631,608 |
Stock repurchase program, average price per share (in dollars per share) | $ / shares | $ 63.50 |

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- Definition Total cost of shares repurchased divided by the total number of shares repurchased. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655 + Details
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- Definition Number of shares that have been repurchased during the period and are being held in treasury. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 + Details
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